The invention relates to improvements in apparatus for brewing hot beverages, such as coffee, tea, chocolate and soups. More particularly, the invention relates to improvements in apparatus of the type wherein freshly brewed beverage is caused to descend, normally by gravity flow, from a holder into a vessel (such as a coffee pot or a tea pot) which is supported at a level below the holder. Still more particularly, the invention relates to improvements in mechanisms which are used to prevent hot beverage from dripping onto parts of the apparatus below the outlet or outlets of the holder when the beverage-collecting vessel is not in place and/or when the holder is moved to a position away from alignment with a vessel on its support.
An electric coffee maker normally comprises a housing which carries or embodies a container for a supply of fresh water and which contains an electric water heater. Cold water is conveyed from the container through or past the heater, and the thus heated water is caused to flow up a riser and into a holder for a filter wherein the water contacts a flavoring agent (e.g., a metered quantity of comminuted coffee beans). The resulting beverage is discharged by way of one or more outlets in the bottom of the filter and is gathered in a vessel (e.g., a coffee pot made of glass or plastic material) which is positioned on a support beneath the holder. The outlet or outlets are controlled by one or more valves which must be opened when the vessel is maintained in proper position beneath the holder in order to establish one or more paths for the flow of coffee from the holder into the vessel. In order to automate the opening of the valve or valves, the cover for the coffee pot is caused to cooperate with an actuator which is installed in or on the housing of the coffee maker and is engaged by the cover of a properly positioned coffee pot to thereby open the valve or valves The outflowing beverage must pass through a centrally located opening in the cover of the properly positioned coffee pot.
The reason that the valve or valves are not opened directly by the coffee pot (instead of by the cover) is that, as a rule, the pot is provided with a spout which extends downwardly below a rim surrounding the major part of the open top of the pot. If the coffee maker employs a lever-like actuator which is pivotable relative to the housing or relative to the holder in order to open or close the valve or valves, the lever is likely to overlie the spout of a properly positioned pot. This enables the lever to assume a position in which the valve or valves are closed even though the pot is ready to receive freshly brewed hot coffee. If the lever (or an otherwise configurated actuator) is positioned and dimensioned to be pivoted by the cover, the orientation of the spout on the pot below the holder for the coffee filter is of no consequence, i.e., the spout can extend in any desired direction without affecting the cooperation between the cover and the actuator. Of course, if the pot does not have a spout, the actuator can include a narrow lever which is engaged by the rim of a cup or pot beneath the holder to maintain the valve or valves in open position. In such coffee makers, the angular position of the pot or cup is of no consequence. Reference may be had to commonly owned U.S. Pat. Nos. 4,790,240 and 4,843,955 respectively granted Dec. 13, 1988 to Henn et al. and July 4, 1989 to Henn et al. Commonly owned U.S. Pat. No. 4,811,657 (granted March 14, 1989 to Rixen) discloses a valve adapted to be opened by a pivotable actuator which is located in the path of the cover on top of a vessel. The actuator opens the valve as soon as it is engaged by the cover of a properly positioned coffee pot or another suitable vessel. The cover has an opening which enables hot coffee to flow from the filter holder into the interior of the vessel.
Proper sealing of the outlet or outlets when the pot is not in position to receive hot beverage is important and highly desirable because the outflowing beverage could contaminate the warming plate for the pot and/or penetrate into the interior of the housing to cause damage to various electrical and electronic components which are normally installed in the hollow base of the housing. Therefore, the valve or valves include springs which bias the valving element or elements to operative or sealing position(s) and are free to dissipate energy as soon as the pot is removed from its support or is shifted along the support to a position in which it is unable to intercept a stream or discrete droplets of hot beverage. Penetration of droplets of hot beverage into the base of the housing can be prevented only by resorting to costly and complex sealing devices. Moreover, dried beverage on the upper side of the warming plate and/or on other exposed surfaces of the coffee maker detracts from the appearance of such apparatus.
Heretofore known actuators for the valve or valves which control the outflow of hot beverage from the filter holder of a coffee maker or a like beverage brewing apparatus normally comprise a one-armed lever or a two-armed lever. A two-armed lever is normally used in apparatus wherein the filter holder is pivotably or reciprocably mounted on the upper portion of the housing. Such movability of the holder is often desirable because a holder which has been pivoted or otherwise moved from operative position affords convenient access to the filter and to the filter bag therein. On the other hand, one-armed levers are used in coffee makers and like apparatus wherein the holder is fixedly mounted in the housing so that access to a filter therein can be gained by pivoting a closure or lid at the top of the housing to open position.
Practically all heretofore known coffee makers are designed in such a way that the actuator for valve or valves in the holder is pivoted by a cover of the coffee pot. Reference may be had again to U.S. Pat. No. 4,811,657 to Rixen. It is also known to provide the central portion of the cover with a substantially hemispherical external protuberance which directly engages a valve at the underside of the holder when the pot is properly positioned with reference to the holder. The valve closes as soon as the protuberance of the cover is moved away, i.e., as soon as the pot is shifted relative to the warming plate on the base of the housing of the coffee maker. The means for automatically closing the valve includes a spring which stores energy while the valve is directly engaged by the protuberance of the properly positioned cover. The spring ensures that the valve cannot jam in the open position and invariably seals the outlet or outlets of the holder as soon as the pot is no longer in position to intercept the hot beverage.
It is further known to indirectly influence a lever which serves to open a valve in the holder in response to proper positioning of the coffee pot below the holder.
The utilization of a cover or lid as a means for directly or indirectly opening a valve in the holder of a coffee maker or a like machine exhibits certain serious drawbacks. Thus, it is necessary to employ a relatively strong and stiff cover because a weaker and more readily deformable cover could yield to the pressure of the spring or springs which are used to normally maintain the valve or valves in closed position(s). A deformed cover is incapable of reliably opening the valve or valves when the pot is in proper position for reception of hot beverage The utilization of weaker springs is not a satisfactory solution because a weaker spring might not be able to reliably close the valve when the cover is disengaged from the valve or from an actuator (e.g., a one-armed of multi-armed lever) for the valve. A flexible cover contributes to greater tolerances between relatively movable parts. Such tolerances are compounded with certain other tolerances, e.g., those which are unavoidable when a coffee pot is made of glass or another non-metallic material. The just discussed tolerances are much less troublesome if the coffee pot is furnished with a rigid cover, i.e., with a relatively heavy and bulky cover which, in turn, is undesirable for many other reasons. Moreover, an overly rigid cover is likely to damage the valve or the actuator.
Another drawback of the aforediscussed conventional beverage brewing apparatus is that the valve or valves in the holder cannot be opened if the cover is misplaced or destroyed. This can result in overfilling of the holder and in overflowing of hot beverage from the holder.
French Pat. No. 2 439 042 to SEB S.A. discloses a coffee maker wherein the vessel for gathering a freshly brewed beverage comprises a cover with a centrally located opening. The holder above the support for the vessel carries a small pivotably mounted receptacle which prevents dripping of hot beverage from the holder onto the support for the vessel when the vessel is moved off the support. The receptacle is held in liquid-collecting position under the action of gravity but is tilted by the vessel when the latter is moved onto its support beneath the holder for flavoring agent. The bottom wall of the receptacle carries a downwardly extending projection in the form of a tooth which is to be engaged by the cover of the oncoming vessel in order to tilt the receptacle and to thus establish an unobstructed path for the flow of freshly brewed beverage from the interior of the holder into the vessel below it. If the vessel is moved toward a proper position on the support in a particular direction, the spout in the rim at the top of the vessel is likely to engage the projection of the receptacle before the projection comes into actual engagement with the cover. The width of the projection is a small fraction of the width of the spout. At any rate, the receptacle is maintained in tilted position only by the cover not later than when the movement of the vessel onto its support beneath the holder is completed. The projection engages the surface bounding the spout only if the vessel is introduced into the apparatus at right angles to the direction which is indicated by arrow F1 in FIG. 4 of the French reference.
Published European patent application No. 0 019 291 of Lemoine discloses a coffee maker wherein the valve in the bottom part of the holder for a filter is opened by the cylindrical wall of a coffee pot in response to movement of the pot to a position beneath the holder. The lower portion of the cylindrical wall of the pot pivots a lever which, in turn, pivots the valving element on one arm of a bell crank lever to open or inoperative position. Neither the top of the pot nor the cover at the top of the pot is used as a means for opening the valve in response to proper positioning of the pot on its support so that the pot is ready to receive a stream of hot beverage which first impinges upon the cover and thereupon descends into the pot by way of a central opening in the cover.
Published European patent application No. 0 328 744 of Wunder et al. discloses a coffee maker wherein the opening of the valve at the lower end of the holder takes place in two stages. The first stage involves insertion of the holder into the housing whereby a lever of the holder pivots as a result of engagement with a cam in the housing and a portion of the lever moves into the path of advancement of the coffee pot toward its operative or beverage-receiving position. The cover of the pot then engages and pivots the lever so that the latter opens the valve and permits hot beverage to flow from the interior of the holder into the pot.
German Auslegeschrift No. 26 05 957 of Arbter et al. discloses a coffee maker wherein a follower tracks a specially configurated cover at the top of a pot which is being moved toward operative position below the filter holder. The cover pivots the follower so that the latter opens the valve at the lower end of the holder and permits hot beverage to descend into the pot. The cover has a central opening for the beverage.
German Utility Model No. 84 37 676.7 of Bosch-Siemens describes a coffee maker wherein the valve for the outlet at the bottom end of the filter holder is mounted on a lever which can be pivoted by the coffee pot. The reference further discloses a mechanism which can be operated to raise or lower the filter holder. The detailed description does not mention a cover for the pot; however, the introductory part of the reference states that the apparatus of Bosch-Siemens is an improvement over apparatus of the type wherein a sensor or actuator cooperates with the cover of a coffee pot. Bosch-Siemens specifically refers to German Utility Model No. 76 04 370.
Published European patent application No. 0 091 634 of Amiot describes a coffee maker wherein the valve at the bottom of the filter holder can be opened to a greater or lesser extent, i.e., the freshly brewed hot beverage can flow into the pot at a faster rate or at a slower rate. The actuator for the valve is moved by the cover at the top of the coffee pot.